The pam_env module in Linux-PAM (aka pam) 1.1.2 and earlier reads the .pam_environment file in a user's home directory, which might allow local users to run programs with an unintended environment by executing a program that relies on the pam_env PAM check.

The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2010-0891 advisory.

    - fix insecure dropping of priviledges in pam_xauth, pam_env,       and pam_mail - CVE-2010-3316 (#637898), CVE-2010-3435 (#641335)

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote host is affected by the vulnerability described in GLSA-201206-31 (Linux-PAM: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in Linux-PAM. Please       review the CVE identifiers referenced below for details.
  Impact :

    A local attacker could use specially crafted files to cause a buffer       overflow, possibly resulting in privilege escalation or Denial of       Service. Furthermore, a local attacker could execute specially crafted       programs or symlink attacks, possibly resulting in data loss or       disclosure of sensitive information.
  Workaround :

    There is no known workaround at this time.

Updated pam packages that fix three security issues are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

Pluggable Authentication Modules (PAM) provide a system whereby administrators can set up authentication policies without having to recompile programs that handle authentication.

It was discovered that the pam_namespace module executed the external script namespace.init with an unchanged environment inherited from an application calling PAM. In cases where such an environment was untrusted (for example, when pam_namespace was configured for setuid applications such as su or sudo), a local, unprivileged user could possibly use this flaw to escalate their privileges. (CVE-2010-3853)

It was discovered that the pam_env and pam_mail modules used root privileges while accessing user's files. A local, unprivileged user could use this flaw to obtain information, from the lines that have the KEY=VALUE format expected by pam_env, from an arbitrary file.
Also, in certain configurations, a local, unprivileged user using a service for which the pam_mail module was configured for, could use this flaw to obtain limited information about files or directories that they do not have access to. (CVE-2010-3435)

Note: As part of the fix for CVE-2010-3435, this update changes the default value of pam_env's configuration option user_readenv to 0, causing the module to not read user's ~/.pam_environment configuration file by default, as reading it may introduce unexpected changes to the environment of the service using PAM, or PAM modules consulted after pam_env.

It was discovered that the pam_xauth module did not verify the return values of the setuid() and setgid() system calls. A local, unprivileged user could use this flaw to execute the xauth command with root privileges and make it read an arbitrary input file.
(CVE-2010-3316)

Red Hat would like to thank Sebastian Krahmer of the SuSE Security Team for reporting the CVE-2010-3435 issue.

All pam users should upgrade to these updated packages, which contain backported patches to correct these issues.

ID	Name	Product	Family	Severity
68144	Oracle Linux 6 : pam (ELSA-2010-0891)	Nessus	Oracle Linux Local Security Checks	high
59704	GLSA-201206-31 : Linux-PAM: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	high
50644	RHEL 6 : pam (RHSA-2010:0891)	Nessus	Red Hat Local Security Checks	high

Detections

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CVE-2010-4708

high

Tenable Plugins

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